WO2002021055A2 - Procede et dispositif destines a fournir une indication de la composition d'un fluide, notamment dans des pompes a chaleur et des vaporisateurs - Google Patents

Procede et dispositif destines a fournir une indication de la composition d'un fluide, notamment dans des pompes a chaleur et des vaporisateurs

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Publication number
WO2002021055A2
WO2002021055A2 PCT/IL2001/000836 IL0100836W WO0221055A2 WO 2002021055 A2 WO2002021055 A2 WO 2002021055A2 IL 0100836 W IL0100836 W IL 0100836W WO 0221055 A2 WO0221055 A2 WO 0221055A2
Authority
WO
WIPO (PCT)
Prior art keywords
fluid
examined
thermistor
evaporator
working fluid
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/IL2001/000836
Other languages
English (en)
Other versions
WO2002021055A3 (fr
Inventor
Gady Golan
Zeev Shavit
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ATCT Advanced Thermal Chip Technologies Ltd
Original Assignee
ATCT Advanced Thermal Chip Technologies Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ATCT Advanced Thermal Chip Technologies Ltd filed Critical ATCT Advanced Thermal Chip Technologies Ltd
Priority to AU2001288022A priority Critical patent/AU2001288022A1/en
Publication of WO2002021055A2 publication Critical patent/WO2002021055A2/fr
Publication of WO2002021055A3 publication Critical patent/WO2002021055A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N25/00—Investigating or analyzing materials by the use of thermal means
    • G01N25/18—Investigating or analyzing materials by the use of thermal means by investigating thermal conductivity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/30—Expansion means; Dispositions thereof
    • F25B41/31—Expansion valves
    • F25B41/34—Expansion valves with the valve member being actuated by electric means, e.g. by piezoelectric actuators
    • F25B41/35—Expansion valves with the valve member being actuated by electric means, e.g. by piezoelectric actuators by rotary motors, e.g. by stepping motors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B49/00—Arrangement or mounting of control or safety devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
    • G01N27/14—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of an electrically-heated body in dependence upon change of temperature
    • G01N27/18—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of an electrically-heated body in dependence upon change of temperature caused by changes in the thermal conductivity of a surrounding material to be tested
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2400/00—Component parts or details not otherwise provided for in this subclass
    • F25B2400/08—Refrigeration machines, plants and systems having means for detecting the concentration of a refrigerant
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/04—Refrigerant level
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B30/00—Heat pumps
    • F25B30/02—Heat pumps of the compression type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B39/00—Evaporators; Condensers
    • F25B39/02—Evaporators
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
    • Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Definitions

  • the present invention relates to a method and apparatus for providing an indication of the composition of an examined fluid.
  • the invention is particularly useful in a heat pump for indicating the physical, or phase, composition of the working fluid (i.e., the relative proportions of the working fluid in the liquid and vapor phases) at one or more stages of the heat pump cycle.
  • Another application is for indicating the liquid level in a vaporizer. The invention is therefore described below particularly with respect to these two applications, but it will be appreciated that the invention is useful in many other applications.
  • Heat pumps are widely used for heating and/or cooling purposes. They include a phase-changing working fluid driven through a closed loop including a compressor, a condenser, an expansion valve, and an evaporator.
  • the proper and efficient operation of such a heat pump depends to a considerable degree on the ability to control the physical composition of the working fluid (i.e., the relative proportions in the liquid and vapor phases) at the different stages of the closed loop cycle, particularly at the inlet to the evaporator, and at the outlet from the evaporator.
  • VCS Vapor Cycle Systems
  • the invention relates to a method of providing an indication of the composition of an examined fluid, comprising: immersing an electrical resistor within the examined fluid; applying electrical current through the electrical resistor to heat it to a temperature above that of the examined fluid; measuring the rate of heat dissipation from the electrical resistor via the examined fluid to provide a measurement of the thermal heat dissipation (THD) of the examined fluid; and comparing the measured thermal heat dissipation of the examined fluid with the known thermal heat dissipation of different fluid compositions to provide an indication of the composition of the examined fluid.
  • TDD thermal heat dissipation
  • the rate of heat dissipation is measured by controlling the electrical current applied through the electrical resistor to maintain the electrical resistor substantially at a predetermined temperature while the electrical resistor is immersed in the fluid, and measuring the electrical current applied through the electrical resistor to maintain it substantially at the predetermined temperature.
  • the electrical resistor is a positive temperature coefficient (PTC) thermistor.
  • PTC positive temperature coefficient
  • Such thermistors can be constructed by known doping and sintering processes to have a maximum predetermined temperature irrespective of the power supplied to the thermistor, thereby obviating the need for additional controls or temperature sensors when used as the electrical resistor immersed in the fluid to be examined in accordance with the present invention. Many other important advantages in the use of such thermistors are described below.
  • the invention is particularly useful where the fluid is examined for its physical composition, e.g., to determined the relative proportions thereof in the liquid and gaseous phases.
  • One particular application of the invention is in the examination of a phase-changing working fluid in one or more stages of a heat pump for indicating the proportions of the working fluid in the liquid and vapor phases at the respective stage of the heat pump cycle.
  • the results of the examination of the working fluid may be used for optimizing the heat pump cycle, as well as for detecting leakage of working fluid, etc.
  • the fluid is a liquid in a vaporizer inlet, and is examined at one or more levels therein to indicate the vapor content in the vaporizer outlet.
  • the invention may also be used for determining the chemical composition of a fluid, (e.g., a mixture of different fluids having different thermal properties) in which case the measured thermal property of the examined fluid would be compared with the known thermal property of fluids of different compositions to provide an indication of the chemical composition of the examined fluid.
  • a fluid e.g., a mixture of different fluids having different thermal properties
  • the fluid When the invention is used for indicating either the physical composition or the chemical composition of a fluid, the fluid should of course be non-flowing, or flowing at a known velocity, so that the measured thermal conductivity can be compared to the known thermal property of other fluids under the same velocity conditions. Once the fluid has been examined to provide an indication of its composition, it may then be examined while flowing at an unknown velocity also to indicate its velocity.
  • the invention also relates to apparatus for providing an indication of the composition of an examined fluid, comprising: an electrical resistor having a mounting device for mounting the electrical resistor immersed in the fluid to be examined; a power supply for supplying electrical current to the electrical resistor to heat it to a temperature above that of the examined fluid; and a processor for: (a) controlling the heating current applied to the electrical resistor to maintain the electrical resistor substantially at a predetermined temperature; (b) measuring the electrical current applied to the electrical resistor to maintain it substantially at the predetermined temperature; and (c) producing an output, based on the measured electrical current, indicating the composition of the examined fluid.
  • PTC positive temperature coefficient
  • Fig. 1 are curves illustrating the temperature - resistance relationship of three typical positive temperature coefficient (PTC) thermistors
  • Fig. 2 is a three-dimensional magnified view illustrating one form of PTC thermistor particularly useful as a fluid sensor in the present invention
  • Fig. 3 illustrates one form of sensor constructed in accordance with the present invention incorporating a PTC thermistor for monitoring the physical composition of a fluid to be examined;
  • Figs. 4 and 5 are enlarged sectional and end views, respectively, more particularly illustrating the structure of the sensor elements in the sensor of Fig. 3, Fig. 4 being a sectional view along line IV — IV of Fig. 5;
  • Fig. 6 is a circuit diagram illustrating the circuitry included in the sensor of Figs. 3 - 5;
  • Fig. 7 is a block diagram illustrating the overall apparatus including the PTC thermistor sensor of Figs. 3 - 6 for examining a fluid to indicate its composition;
  • Fig. 8 is a diagram illustrating one preferred embodiment of the invention, namely for detecting the physical composition of a working fluid (i.e., the relative proportions of the working fluid in the liquid and vapor states) in different stages of a heat pump cycle in order to optimize the cycle as well as to indicate possible leakage of the working fluid;
  • a working fluid i.e., the relative proportions of the working fluid in the liquid and vapor states
  • Fig. 9 is a diagram illustrating one manner of controlling the expansion valve in the heat pump cycle of Fig. 8.
  • Fig. 10 illustrates a second embodiment of the invention, as applied for indicating the liquid level in a vaporizer.
  • the present invention is based on the fact that the rate of heat dissipation produced by a fluid with respect to an electrical heater immersed in the fluid is related to the thermal properties of the fluid. Measuring the rate of heat dissipation has previously been used to provide an indication of the rate of flow of the fluid.
  • the present invention utilizes the rate of heat dissipation to provide an indication of the composition of the fluid.
  • the method is used to provide an indication of the physical composition of the fluid, particularly the relative proportions of the fluid in the liquid and vapor states.
  • the invention could also be advantageously used for providing an indication of the species composition of the fluid.
  • the electrical heater could, theoretically, be any type of electrical heater wherein the rate of heat dissipation is measured by controlling the electrical current through the electrical resistor to maintain it substantially at a predetermined temperature while the resistor is immersed in the fluid, and measuring the electrical current through the electrical resistor to maintain it substantially at the predetermined temperature.
  • the electrical resistor is a positive temperature coefficient (PTC) thermistor.
  • PTC positive temperature coefficient
  • Such a thermistor when operating at a preset maximum temperature, produces a current flow directly related to the thermal load, in this case, to the heat dissipation rate produced by the fluid in which the thermistor is immersed.
  • TJ is the heat transfer coefficient (h multiplied by the sensor's surface area); Ts is the sensor's temperature; and Tf is the fluid temperature.
  • the invention is particularly useful in indicating the relative proportions of a working fluid in the liquid phase and in the gas phase at various locations in a Vapor Cycle System (VCS), such as a heat pump for cooling or heating air.
  • VCS Vapor Cycle System
  • the heat transfer coefficient (TJ) for the liquid phase is at least ten times higher than that of the gas phase, whereas the temperature difference (Ts-Tf) usually does not vary more than 5 times between the lowest and highest temperature difference level.
  • Ts-Tf temperature difference
  • the sensor temperature (Ts) remains relatively constant within a range of 5°C. It is therefore expected that the sensor's heat-load, which is exposed to the gas flow, will be at least 5 times lower than that of the liquid flow, even if the fluid temperature Tf varies maximally as expected.
  • the range of the fluid temperature (Tf), measured after the thermal expansion valve (TXV), is between 0 °C to 25 °C during a normal operation.
  • the fluid temperature (Tf) moves towards the ambient temperature.
  • the power dissipation of the PTC sensor (Ps) is equal to the heat load (Q): therefore, for a constant voltage power supply, the sensor's resistance Rs varies with Q, as:
  • the sensor's current consumption, Is changes accordingly; thus:
  • the PTC thermistor sensor can thus be used for sensing the rate of heat dissipation, and thereby the thermal conductivity, of the fluid in which the thermistor is immersed when the fluid is either relatively stationary, or moving at a known velocity. It will also be appreciated that, when the composition of the examined fluid has been determined in the above-described manner, the same technique can also be used for determining the rate of flow of the fluid.
  • the preferred embodiments of the invention described below utilize a PTC thermistor sensor as the electrical resistor immersed within the fluid to be examined.
  • a PTC thermistor sensor as the electrical resistor immersed within the fluid to be examined.
  • using such a thermistor for the sensor obviates the need for additional controls or temperature sensors since Ihe temperature of the sensor does not rise significantly above its maximum temperature irrespective of the voltage applied to it.
  • a preferred PTC thermistor is one made of barium titanate, since this material is characterized by a very high resistance to corrosion and a relatively low hazard to explosion when exposed to certain gases. Fig.
  • Fig. 1 includes curves illustrating the temperature-resistance relationship of three typical PTC thermistor, wherein it will be seen that at a preset temperature, depending on the composition of the thermistor, the resistance grows abruptly virtually to infinity.
  • Fig. 2 is a three-dimensional view illustrating one form of sensor unit, generally designated 2, including one or more such thermistors.
  • the thermistor is preferably of barium titanate produced by a sintering process and doped according to the desired maximum temperature, enclosed within a housing of thermally-conductive, electrically-insulating material, such as AL 2 0 3 , and is provided with electrodes 3, 4, for connection to the electrical supply.
  • the outer surfaces of the sensor unit 2 are preferably coated with a conductive metal, such as aluminum, in order to provide good thermal contact with the fluid in which the sensor is immersed.
  • Fig. 3 illustrates a sensor assembly for mounting the sensor unit 2 to a housing containing the fluid to be examined.
  • the housing may be, for example, a container containing the fluid to be examined, or may be a conduit through which the fluid to be examined flows.
  • the sensor assembly illustrated in Fig. 3, and therein designated 10 mounts the sensor unit 2 in the housing such that the sensor unit is completely immersed within the fluid in the housing.
  • the sensor assembly 10 illustrated in Fig. 3 includes the sensor unit 2 at one end 12 carried by a fitting 12, and a mounting device 14 at the opposite end, such as a threaded member, for mounting the sensor unit 2.
  • the sensor assembly 10 further includes a housing 16 for the sensor circuitry 18 (as illustrated in Fig. 6) and output leads 19 for outputting the signal from the sensor circuit 18.
  • the sensor circuitry 18 includes two sensor units: one sensor unit is exposed to the fluid being examined, whereas the other sensor unit serves as a reference and is not exposed to the fluid being examined.
  • Figs. 4 and 5 illustrate such a sensor assembly, in which one sensor unit 2a is left bare so as to be exposed to the fluid being examined, whereas the other sensor unit 2b is enclosed within a metal housing 20 so as to be shielded from the fluid being examined. Both are carried by a plug mounting device 22.
  • the exposed sensor unit 2a is embedded within a sealing material 24, except for its outer end which is exposed to the fluid being examined.
  • the metal housing 20 enclosing the reference sensor unit 2b also includes a liquid thermally insulating material 26.
  • the electrical circuit 18 within housing 16 is more particularly illustrated in Fig. 6.
  • the circuit is in the form of a bridge having two legs 31, 32 including a resistor Rl, a third leg 33 including a reference PTC thermistor sensor 2b, and a fourth leg 34 including the PTC thermistor sensor 2a to be immersed in the fluid being examined.
  • reference sensor 2b should be identical to the measuring sensor 2a, but is not immersed in the fluid being examined.
  • Sensor 2a thus provides a measurement of the heat dissipation, and thereby of the thermal conductivity, of the fluid being examined.
  • the electrical circuit 18 within the sensor assembly (10, Fig. 3, or 20, Figs. 4, 5) further includes a comparator 35 having a first input 35a connected to the juncture between the two resistors Rl of the first two legs 31, 32, and a second input 35b connected to the juncture of the two PTC thermistor sensors 2a, 2b in legs 33, 34.
  • the output from the comparator 35 is amplified by a transistor 36 before appearing in the output leads 19.
  • Fig. 7 is a block diagram illustrating the overall apparatus including the PTC thermistor sensor circuit 18 included in the sensor assembly 10 (or 20).
  • the apparatus includes a power supply 40 for supplying electrical current to the two thermistor sensors 2a, 2b of the thermistor sensor circuit 18; and a processor 41 for controlling the power supply 40 to control the heating current applied to the two thermistor sensors in order to maintain them substantially at their respective predetermined temperatures.
  • Processor 41 also measures the electrical current applied to thermistor sensor 2a to maintain it substantially at its predetermined temperature, and produces an output, shown at 42, indicating the composition of the examined fluid in which thermistor sensor 2a was immersed. As briefly described earlier, this output is produced by comparing the measured thermal conductivity of the examined fluid with the known thermal properties of different fluid compositions to thereby provide an indication of the composition of the examined fluid.
  • the output from processor 41 indicating the fluid composition may be used for control purposes, as shown at 43, for display purposes as shown at 44, or for record purposes as shown at 45.
  • Fig. 8 illustrates the invention implemented in a Vapor Cycle System (VCS) of a heat pump, for detecting the physical composition of the working fluid, i.e., the relative proportions of the working fluid in the liquid and vapor phases in particular stages of the VCS cycle.
  • VCS Vapor Cycle System
  • the Vapor Cycle System (VCS) illustrated in Fig. 8 includes a phase-changing working fluid driven through a closed loop, comprising a compressor 51, a condenser 52, an expansion valve 53, and an evaporator 54.
  • the expansion valve 53 is connected via a liquid phase line 55 to the inlet of the evaporator 54; and the outlet from the evaporator is connected via a gas phase line 57 to the compressor 51.
  • Fig. 8 illustrates a first PTC thermistor sensor 61 in the liquid phase line 55, to provide an indication of the state of the working fluid in the liquid phase line 55 between the expansion valve 53 and the inlet to the evaporator 54.
  • the system in Fig. 6 includes a second PTC thermistor sensor 62 in the gas phase line 56 to provide an indication of the state of the working fluid fed from the outlet of the evaporator 54 to the compressor 51.
  • the working fluid be substantially completely in the liquid phase at the location where examined by the PTC thermistor sensor 61, and be substantially completely in the vapor state where examined by the PTC thermistor sensor 62.
  • Such sensors can also be used to provide an indication of whether working fluid is leaking from the VCS, and where.
  • the system illustrated in Fig. 8 further includes a processor 63 for controlling the power supply supplying the electrical current to the two thermistor sensors 61, 62 to maintain them substantially at their respective predetermined temperatures, and thereby to enable them to measure the heat conductivity of the working fluid at the respective stage of the cycle.
  • Processor 63 also measures the electrical current applied to the thermistor sensors 61, 62 to maintain them substantially at their respective maximum temperatures, such that the current supplied to the thermistor sensors will provide an indication of the physical composition (i.e., its liquid/vapor state) of the working fluid at the respective location.
  • the microprocessor 63 also produces an output which is used for controlling the expansion valve 53 in response to the measurements made by the thermistor sensor 61.
  • processor 63 produces an output to a driver 64 which drives a position controller 65 coupled to the expansion valve 33 to control the latter valve.
  • Fig. 9 more particularly illustrates one possible manner in which the expansion valve 53 may be controlled by the processor 63.
  • the valve driver 65 is a step motor which drives a conical valve head 66 with respect to a complementary-shaped conical passageway 67 within the housing 68 of the expansion valve 53. Passageway 67 is coupled to the outlet of condenser 52, whereas the interior of housing 68 is coupled to the liquid phase line 55 leading to the inlet of the evaporator 54.
  • the output from the processor 63 is utilized, via the driver circuit 64 and the step motor 65, to control the spacing between the conical valve head 66 and the passageway 67 within the expansion valve 53, and thereby the degree of expansion of the fluid (liquid) fed from the condenser 52 via the liquid phase line 55 to the inlet of evaporator 54.
  • Other expansion control valves can be used, e.g., according to the known solenoid PWM 19 system or other systems.
  • the system may be used with thermal expansion valve with a refrigerant pressure bulb, in which the bulb temperature is controlled by a small thermoelectric component by a controller such as shown at 64 in Fig. 8.
  • Fig 10 illustrates the invention implemented in a liquid vaporizer, generally designated 70, to provide an indication of the liquid level within the vaporizer.
  • the vaporizer includes a container 71 having a liquid (e.g., water) inlet 72 and a vapor outlet 73.
  • the liquid within the container is heated by a heater 74 immersible in the liquid.
  • the heater 74 is also a PTC thermistor, but may be any other type of electrical heater commonly used for heating water or other liquids.
  • the vaporizer illustrated in Fig. 10 includes a PTC thermistor sensor assembly 75 at the desired liquid high-level location within container 70, and a second PTC thermistor sensor assembly 76 at the desired low-level location.
  • Each of the sensor assemblies 75, 76 may be of the construction described above with respect to Figs. 3 - 6. Their outputs may be used for signaling purposes or for control purposes.
  • the output of the PTC thermistor sensor assembly 75 may be used for controlling the inflow of the liquid via the inlet 72 to maintain the liquid level at that location of the container; whereas the output of the PTC thermistor assembly 76 may be used for sounding an alarm and/or for disconnecting the power supply to the heater 74 in case the level of the liquid drops below that level in the container.
  • impingement of liquid droplets on the PTC thermistor sensor would immediately increase the thermal load on the thermal sensor, manifested by an increase in its current, such that positioning the sensor in a specific location, e.g., in a small diffuser which reduces local pressure, will produce an alarm signal right before penetrating a condensation condition in the main stream.
  • the invention could also be used for indicating the chemical composition of a fluid, by comparing its measured thermal conductivity with the known thermal conductivities of various known materials. Also, once the composition of a material is indicated in the manner described above, the invention could also be used for measuring the flow velocity of that material.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Biochemistry (AREA)
  • General Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Investigating Or Analyzing Materials Using Thermal Means (AREA)
  • Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
  • Filling Or Discharging Of Gas Storage Vessels (AREA)

Abstract

L'invention concerne un procédé et un dispositif permettant d'obtenir une indication relative à la composition d'un fluide en cours d'analyse à l'aide d'une résistance électrique, et notamment d'une thermistance à coefficient de température positif, en vue de mesurer la conductivité thermique de ce fluide en cours d'analyse selon la conductivité thermique connue de différentes compositions de fluide. Ce procédé et ce dispositif permettent notamment d'indiquer les proportions relatives d'un fluide actif dans les phases liquide et vapeur d'un ou plusieurs étages d'une pompe à chaleur. L'invention se rapporte également à une autre application destinée à indiquer le niveau de liquide dans un vaporisateur de liquide.
PCT/IL2001/000836 2000-09-05 2001-09-05 Procede et dispositif destines a fournir une indication de la composition d'un fluide, notamment dans des pompes a chaleur et des vaporisateurs Ceased WO2002021055A2 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2001288022A AU2001288022A1 (en) 2000-09-05 2001-09-05 Method and apparatus for providing an indication of the composition of a fluid particularly useful in heat pumps and vaporizers

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US22973400P 2000-09-05 2000-09-05
US60/229,734 2000-09-05
US09/791,684 US6509553B2 (en) 2000-09-05 2001-02-26 Method and apparatus for providing an indication of the composition of a fluid particularly useful in heat pumps and vaporizers
US09/791,684 2001-02-26

Publications (2)

Publication Number Publication Date
WO2002021055A2 true WO2002021055A2 (fr) 2002-03-14
WO2002021055A3 WO2002021055A3 (fr) 2002-12-19

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Country Status (3)

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US (1) US6509553B2 (fr)
AU (1) AU2001288022A1 (fr)
WO (1) WO2002021055A2 (fr)

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US7036367B2 (en) * 2003-05-20 2006-05-02 A.T.C.T. Advanced Thermal Chips Technologies Ltd. Flow velocity measurement method and apparatus, including applications thereof for measuring heat flow, and wind velocity and/or direction generation
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WO2002021055A3 (fr) 2002-12-19

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